JP2005-325841A (hereinafter referred to as Patent reference 1) discloses a control valve applied to a variable valve timing control device for controlling and changing an opening and closing timing of an intake valve and an exhaust valve provided at each of cylinders during an operation of an internal combustion engine. The control valve disclosed in Patent reference 1 includes an operation fluid supply source port (pressure medium connection portion), two supply and exhaust ports (operation connection portions) supplying and exhausting the operation fluid to two operation fluid supply portions, and two drain ports (tank connection portions) exhausting the operation fluid returning from the mentioned two operation fluid supply portions. That is, the drain ports corresponding to the supply and exhaust ports are provided, respectively.
According to the construction of the control valve disclosed in Patent reference 1, two supply and exhaust ports and two drain ports are necessary for two operation fluid supply portions. Further, although a fluid passage structure for controlling a lock mechanism provided at the variable valve timing control device is not explicitly disclosed in Patent reference 1, additional supply and exhaust port and drain port are necessary for the control valve in order to operate the lock mechanism with the common control valve. The same number of ports to the supply and exhaust ports and the drain ports provided at the control valve are required at the internal combustion engine where the control valve is mounted. Thus, as the number of ports formed at the control valve increases, the number of ports and fluid passages formed at the internal combustion engine increases, which makes structures of the fluid passages between the control valve and the operation fluid supply portion complex.
A need thus exists for a control valve and an attachment structure for the control valve which is not susceptible to the drawback mentioned above.